The present invention relates to techniques of encoding and decoding video data.
In connection with encoding and decoding techniques for compressing and transmitting video data, an internationally standardized encoding standard as typified by the MPEG (Moving Picture Experts Group) standard has hitherto been available. Among the internationally standardized encoding standards, the H.264/AVC (Advanced Video Encoding) standard, for example, especially has high encoding efficiencies and has been utilized widely as a standard for moving picture compression in ground digital broadcasting, digital video camera, next generation encoding media, cellular phones and so on. The data thus compressed pursuant to the standard as above is decoded in a television receiver, a DVD player and the like and the thus decoded video data is displayed on a display.
Then, JP-A-2003-333540 discloses the frame rate conversion to be carried out by using a motion amount (motion vector) obtained by decoding an encoding stream and the decoded image as well in order to eliminate a blur in moving picture and an unnatural motion which occur when displaying the decoded video data.
In the technique described in the aforementioned Patent Document, a frame rate conversion process is applied to the decoded video data. The frame rate conversion process, however, presupposes that a motion vector and a difference image are transmitted from the encoding side to the decoding side and fails to contribute to reduction in the amount of transmission data, raising a problem that improvements in data compression rate are insufficient.